- = do { let (tvs, rhs) = synTyConDefn tc
- ; rhs' <- reifyType rhs
- ; return (TH.TyConI $ TH.TySynD (reifyName tc) (reifyTyVars tvs) rhs') }
+ = case synTyConDefn tc of
+ Nothing -> noTH SLIT("type family") (ppr tc)
+ Just (tvs, rhs) ->
+ do { rhs' <- reifyType rhs
+ ; return (TH.TyConI $
+ TH.TySynD (reifyName tc) (reifyTyVars tvs) rhs') }